Filter element with pleat support combs

ABSTRACT

A filter element includes support grid secured about its periphery edges to a periphery frame member. A pleated filter media is secured to the frame member and is sized and positioned to fully cover the filter fluid aperture. The support grid is positioned such that it is effective in providing support to the filter media against fluid forces. At least one elongated comb member is provided and includes a plurality of spaced tapered teeth protruding outwards towards the filter media. The teeth are sized and spaced to be received into at least a portion of grooves present between the pleats of the filter media. The teeth of the comb member are sized and spaced to regulate filter media pleat separation and spacing.

TECHNICAL FIELD

The present invention generally relates to a filter element havingpleated filter media and, more particularly, to an improved pleatedfilter element adapted to provide support to and regulate spacing offilter media pleats.

BACKGROUND OF THE INVENTION

Filter elements having pleated filter media are well known in the art.Pleated filter elements are often used to remove particulatecontaminants from a gaseous fluid stream, such as in an intake airstream. Varieties of pleated filter elements find applications inautomotive engine intake systems, air compressor systems as well as inother process and equipment applications where the removal ofcontaminants is highly desired or required.

Depending upon the filter type and application, pleated filter media maybe susceptible to collapsing or folding over of pleats onto adjacentpleats due to fluid forces applied to the pleats by the filtered fluidstream. This can occur as the pleated filter media is generally madefrom a thin filter paper or other porous sheet media that isadvantageously flexible enough to be formed into pleats. The thicknessand material chosen for use as a filter media needs to have filter poresof sufficient size to pass the fluid stream while blocking passage ofundesired contaminants. Generally the use of thinner rather than thickerfilter media elements is preferred so as to reduce the pressure dropacross the filter.

Several solutions have been developed over time to address improvedsupport for filter pleats. In some cases a porous plastic or metallicsheet is provided as a supportive backing sheet to the filter element.This approach, while providing some support to the filter media sheets,does little to support the filter media pleats, permitting the pleats tobe folded over or collapsed by the fluid forces applied to thefiltration media by passage of the filtered fluid.

Another improvement is provided in U.S. Pat. No. 6,524,479 whichdiscloses a pleated filter element including a fold support member inthe shape of a rod that pierces the pleat surfaces of the folds of thefilter media, thereby supportively joining adjacent pleats andregulating spacing of the pleats. This solution requires that holes forthe rod be provided through the filter media, and the presence of anyholes may be susceptible to leakage of unfiltered fluid around thefilter media.

As can be seen, there is a need for a pleated filter element thatincludes a support structure configured to resist fluid forces so as toretain filter media pleats in a spaced and fully erect arrangement andthat overcomes limitations of the prior art.

SUMMARY OF THE INVENTION

One object of the present invention is to provide an improved pleatedfilter element having elements included to regulate the spacing offilter media pleats.

Another object of the present invention is to provide an improvedpleated filter element that includes features providing additionalsupport to the filter media to resist forces induced on the filter mediaby the filtered fluid stream.

Another object of the present invention is to provide a pleated filterand support structure that enables the use of deep filter pleats as deeppleats provide additional filtration surface area and additional flowcapacity in a given size filter housing while also increasing thecapacity of the filter element to entrap dust or dirt removed from thefluid stream by the filter media.

In one aspect of the invention, a filter element has a pleated filtermedia circumferentially surrounded by a supporting frame member thatdefines an aperture for fluid flow therethrough. A support grid isprovided and secured about its periphery edges onto the frame member.The support grid extends across the aperture. The pleated filter mediais secured to the frame member and is sized and positioned to fullycover the aperture such that fluid flowing through the aperture isconstrained to be filtered by the filter media. The support grid ispositioned at a downstream side of the filter media and positioned suchthat it is effective in providing support to the filter media againstfluid forces. At least one elongated comb member is provided on thesupport grid and extends across at least a portion of the aperture. Thecomb member or members include a plurality of spaced tapered teethprotruding outwards towards the filter media. The teeth are sized andspaced to be received into at least a portion of grooves present betweenthe pleats of the filter media. The teeth of the comb member are sizedand spaced to regulate filter media pleat separation and spacing whileproviding support to the pleats.

In another aspect of the invention, the frame element includes anelastomeric seal.

In another aspect of the invention, the elastomeric seal comprisespolyurethane.

In another aspect of the invention, the teeth are uniformly sized andspaced along the comb.

In another aspect of the invention, the support grid further comprisesedge rails extending about periphery edges of the support grid with theedge rails securing the support grid to the frame member.

In another aspect of the invention, the comb members are positioned atan angle greater than zero degrees and less than forty five degreesrelative to the pleats of the filter media.

In another aspect of the invention, the comb members are positioned atan angle substantially perpendicular to the pleats of the filter media.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a prior art pleated filter element;

FIG. 2 is a perspective view of the upstream side of a support gridprovided with a plurality of comb members for supporting pleated filtermedia in a filter element, consistent with the present invention;

FIG. 3 is a schematic sectional illustration of support grid combmembers supporting pleats in a filter media, generally arrangedaccording to section lines A-A of FIG. 2; and

FIG. 4 is a perspective view of a pleated filter element including asupport grid with pleat support comb members configured to install intoa filter housing, consistent with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In prior art pleated filter elements 10, such as schematicallyillustrated in the partial side view in FIG. 1, forces induced on thepleats 12 by the fluid stream 14 may tend to bend or collapse the pleats12 onto each other. As is well known, pleated filter media is generallymade from filter paper or other porous sheet media that isadvantageously flexible enough to be formed into pleats. The flexibilityof the pleats 12 in the filter media may allow forces induced in thepleats 12 by the fluid stream 14 to flatten and compress the pleats 12,thereby reducing filter fluid flow capacity and increasing pressure dropacross the filter element 10.

FIG. 2 is a perspective view of the upstream side of a support grid 50including a plurality of comb members 38 for regulating pleat spacingand supporting pleats of said pleated filter media in a filter element,consistent with the present invention. FIG. 3 is a schematic sectionalillustration of a support grid comb member supporting pleats of anoverlaid filter media, generally arranged according to section lines A-Aof FIG. 2. The support grid 36 includes a plurality of spaced andcross-wise arranged elongated web members 48 extending between andsecured to peripheral edge rails 44 and 46. The web members 48 arecomprised of a material that is substantially rigid and resists flexure.Web members 48 extend across the aperture 24 defined by the edge rails44 and 46. The web members extend through and divide the aperture 24into a plurality of openings 58 that are of ample size to pass the fluidstream 30 essentially without restriction while providing requiredsupport to the filter media. The peripheral edge rails 44 and 46 serveas a support and mounting frame for the elongated web members 48 of thesupport grid 50. In the illustrated embodiment, a plurality of combmembers 38 are provided in a spaced parallel relationship, secured toand extending across web members 48. In the illustrated embodiment, thecomb members 38 extend to and secure to opposing edge rails 44 of thesupport grid 36. Each comb member 38 includes a plurality of spacedtapered teeth 40 arranged to protrude outwardly from the comb member 38in a direction towards the upstream side 32 of the support grid 36. Theteeth 40 are sized and spaced to be received between and to providesupport to the pleats 28 of the filter media 26. The comb members 38 andteeth 40 comprise materials selected to have sufficient rigidity toprovide support to the pleats 28 against fluid forces without undueflexure.

In certain aspects of the invention, the comb members 38 extend fullyacross the fluid flow aperture 24 as defined between the edge rails 44and 46 of the support grid 38. In some aspects of the invention, thecombs may be positioned substantially at right angles to the pleats 28.

FIG. 3 schematically illustrates the pleats 28 of the filter media 26laid over or supportively received onto the teeth 40 of the comb member38. As illustrated in FIG. 3, the teeth 40 have a tooth to adjacenttooth spacing D1 that corresponds to the desired pleat to pleat spacingD1. The tooth to tooth spacing D1 regulates the spacing of the pleats 28of the filter media 26.

Although the grid member 36 provides support to the pleated filter media26, the grid member may not be sufficient to maintain the pleats 28 in aspaced erect configuration such as depicted in FIG. 3. Instead, forcesinduced in the filter media 26 by fluid stream 30 may be sufficient tocompress or flatten the pleats in a fashion such as discussed andillustrated previously with FIG. 1.

Therefore and advantageously, the present invention includes at leastone comb member 38 secured to the support grid 36 extending across atleast a portion of the aperture 24 defined by the edge rail sets 44 and46. Each comb member 38 includes a plurality of spaced tapered teeth 40,generally protruding outwards from the comb member in a directiontowards the upstream side 32 of the filter element 20. The teeth 40 aresized and spaced to be received between and provide support to thepleats 28 of the filter media 26. The comb member 38 and teeth 40include materials selected to have sufficient rigidity to providesupport to the pleats 28 without undue flexure. In preferredembodiments, the comb member 38 extends fully across the aperture 24. Insome preferred embodiments, the comb members 38 are positionedsubstantially at right angles to the pleats 28. In other embodiments,the comb members 38 are positioned at an angle greater than zero degreesand up to forty five degrees relative to pleats 28. Preferably thelength ‘L2’ of the teeth is selected according to the pleat depth ‘L1’of the filter media 26 such that the teeth, when fully inserted intogrooves 42 between the pleats, have a length ‘L2’ sufficient to maintainthe pleats 28 fully extended in their erect position (substantially atlength ‘L1’).

Advantageously, the teeth 40 provide support to the pleats 28 tomaintain the pleats fully erect and prevent the compression and collapseof the pleats as discussed earlier with the prior art of FIG. 1.

Advantageously, the structure of the support grid 36, particularly theelongated web members 48, is configured and adapted to providestructural support to the filter media 26 and pleats 28 whereby thepleats 28 do not appreciably deform when acted upon by forces induced byfluid stream 30. As can be seen in FIG. 3, as fluid stream 30 flows intothe filter media 26, fluid forces tend to press the pleats 28 againstthe teeth 40 of the comb member 38. The teeth 40, being substantiallyrigid, act to support the pleats 28 in a fully erect position (asillustrated in FIG. 3) and regulate the pleat to pleat spacing D1.

The teeth 40 are spaced along the comb member 38 at a tooth to toothspacing D1 selected to match with the desired pleat to pleat foldspacing D1 of pleats 28, such that the teeth 40 are easily positionedinto the grooves 42 between adjoining pleats. Preferably the length ‘L2’of the teeth is selected according to the pleat depth ‘L1’ of the filtermedia 26 such that the teeth, when fully inserted into grooves 42between the pleats, have a sufficient length to maintain the pleats 28fully extended in their erect position. To support the pleats, the teeth40 do not need to fully extend to the pleat depth L1, but may insteadextend far enough into the grooves 42 such that the remaining distanceabove the teeth 40 to the tip of the pleats (L1-L2) is sufficientlyshort such that inherent rigidity properties of the filter media 26 aresufficient to support the pleats 28 in an erect position as illustratedin FIG. 3.

FIG. 4 is a perspective view of one exemplary embodiment of a pleatedfilter element 20 with comb members 38 configured to support pleats 28of the filter element 20 in a fashion as discussed previously with FIGS.2 and 3. The filter element 20 is sized and configured for installationinto a filter housing, such as the illustrated lower housing 52 withclosable cover 54.

In some embodiments, the filter element 20 may utilize what is known inthe art as “deep pleat” technology. In “deep pleat” technology, thepleats 28 may have a pleat depth ‘L1’ of greater than 3 inches. Forexample, deep pleats of 8 inches may be utilized with such a design.Such deep pleats are particularly susceptible to collapse and distortiondue to fluid forces and therefore particularly benefit from the use ofcomb members as in the present invention. The ability to provide andsupport deep pleats is particularly advantageous to filter elementdesign as deep pleats provide additional filtration surface area to agiven frame size, thereby lowering pressure drop across the filterelement and extending the service life between change outs.

In FIG. 4, the pleated filter element 20 includes a frame member 22defining an aperture 24 therethrough. The frame member 22 may be sizedand configured to be received into a filter housing, for example lowerhousing 52 and upper housing 54. The frame member 22 may comprise anelastomeric seal positioned to interface against and seal against a sealledge 56 or wall within the filter housing 52, 54. In an aspect of theinvention the elastomeric seal comprises polyurethane. In certainaspects of the invention, the frame member 22 may consist almostentirely of polyurethane. Polyurethane is a resilient material that issuitable for air filter applications.

At least one porous filter media layer 26 is formed into a pleated orzigzag folded shape and secured along periphery portions to the framemember 22. The pleated filter media 26 is sized to fully cover theaperture 24 such that the filtered fluid stream 30 is confined to flowthrough the filter media 26 to pass from the upstream side 32 to thedownstream side 34 of the filter element 20. In this way, the filtermedia 26 can be effective in removing particulates from the fluid stream30.

A support grid 36 is provided at a downstream side 34 of the pleatedfilter media 26 and is generally secured along its periphery portions tothe frame member 22. Advantageously, support grid 36 is configured andadapted to provide support to the pleated filter media 26 to assist inresisting forces induced on the filter media 26 by fluid stream 30.

Although the grid member 36 provides support to the pleated filter media26, the grid member may not be sufficient to maintain the pleats 28 in aspaced erect configuration such as depicted in FIG. 4. Instead, forcesinduced in the filter media 26 by fluid stream 30 may be sufficient tocompress or flatten the pleats in a fashion such as discussed andillustrated previously with FIG. 1.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims.

1. A filter element, comprising: a frame member defining an aperture forfluid flow therethrough; a support grid having openings therethrough,said support grid secured about periphery edges to said frame member andextending across said aperture; a pleated filter media secured to saidframe member and fully covering said aperture; wherein said support gridis positioned at a downstream side of said filter media, said supportgrid configured and adapted to provide support to said filter mediaagainst forces induced on said filter media by said fluid stream; and atleast one comb member extending across at least a portion of saidaperture, said comb member including a plurality of spaced apart taperedteeth protruding outwards towards said filter media, said teeth sizedand spaced to be received into at least a portion of grooves betweensaid pleats of said filter media; wherein said comb member teeth arespaced to regulate filter media pleat separation and spacing.
 2. Thefilter element of claim 1, wherein said frame element includes anelastomeric seal.
 3. The filter element of claim 2, wherein saidelastomeric seal comprises polyurethane.
 4. The filter element of claim1, wherein said teeth are uniformly sized and spaced.
 5. The filterelement of claim 1, wherein said support grid further comprises edgerails extending about periphery edges of said support grid, said edgerails securing said support grid to said frame member.
 6. The filterelement of claim 1, wherein said comb members are positioned at an anglegreater than zero degrees and less than forty five degrees relative tosaid pleats.
 7. The filter element of claim 1, wherein said comb membersare positioned at an angle substantially perpendicular to said pleats.